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NG0R - KSB2 low audio level

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John Hoaglun-2

NG0R - KSB2 low audio level

I need some help troubleshooting an issue.

K2+KSB2+K160RX+KIO2+KAT2+K60XV+XV144+XV222+XV432+IMA rework module

I have not spent much time using this rig on SSB but I plan to use it to
drive the transverters. So as part of the setup & checkout of the system
I am noticing that my SSB power level seems pretty low compared to my CW
power level. Specifically when I test my transverters I am getting my
expected power on all of them with CW. (The transverter power level on
each unit is setup for driving the input power level for the brick for
that band.)

144: 25w CW --expected
222: 10w CW --expected
432: 10w CW --expected

When I change over to SSB the power level is almost nothing
144: 1-2w SSB
222: less than 1w SSB
432: less than 1w SSB

I am using an Icom HM-36 mic (and have tested with two Heil headsets
with similar results). SSBA=3 and SSBC=4-1

Initially I was thinking that I had an issue with Mic bias but I am not
so sure now. I configure my computer to send modulated CW over SSB to
compare the output level against a native CW signal. The spread matches
the info above.

It appears that my SSB audio level is attenuated for some reason. (The
audio reports are good with no distortion.)

Any suggestions for where to look on the KSB2 or an adjustment that I
might have missed?

73 de NG0R

--
John Hoaglun
NG0R - EN25
http://www.hoaglun.com

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Don Wilhelm-4

Re: NG0R - KSB2 low audio level

John,

To answer your question, I suggest getting the transverters out of the
equation - there are too many variables right now. Let's try to take it
one step at a time.

Do you have an oscilloscope? If so, try 40 meters into a dummy load -
note the amplitude of a CW signal on the 'scope. Then switch to SSB and
speak into the mic - are the SSB peaks as great as the CW amplitude?
They should be. If they are, then the K2 is delivering the full PEP
requested by the power control and you need to look for problems other
than the K2, and your wattmeters may be indicating something other than
the peak power.

If you do not have an oscilloscope, do you have a peak reading
wattmeter? What does that meter say about the SSB peak power?

What I am trying to discover is whether the problem is related to the
base K2 or some problem with the transverters. Taking the transverters
out of the picture and getting a reading on the behavior of the K2 on 40
meters will be revealing.

Please include the vintage (or serial number) of the K2 and when was the
KSB2 option purchased?

73,
Don W3FPR

On 1/16/2011 8:10 PM, John Hoaglun wrote:

> I need some help troubleshooting an issue.
>
> K2+KSB2+K160RX+KIO2+KAT2+K60XV+XV144+XV222+XV432+IMA rework module
>
> I have not spent much time using this rig on SSB but I plan to use it to
> drive the transverters. So as part of the setup& checkout of the system
> I am noticing that my SSB power level seems pretty low compared to my CW
> power level. Specifically when I test my transverters I am getting my
> expected power on all of them with CW. (The transverter power level on
> each unit is setup for driving the input power level for the brick for
> that band.)
>
> 144: 25w CW --expected
> 222: 10w CW --expected
> 432: 10w CW --expected
>
> When I change over to SSB the power level is almost nothing
> 144: 1-2w SSB
> 222: less than 1w SSB
> 432: less than 1w SSB
>
> I am using an Icom HM-36 mic (and have tested with two Heil headsets
> with similar results). SSBA=3 and SSBC=4-1
>
> Initially I was thinking that I had an issue with Mic bias but I am not
> so sure now. I configure my computer to send modulated CW over SSB to
> compare the output level against a native CW signal. The spread matches
> the info above.
>
> It appears that my SSB audio level is attenuated for some reason. (The
> audio reports are good with no distortion.)
>
> Any suggestions for where to look on the KSB2 or an adjustment that I
> might have missed?
>
> 73 de NG0R
>

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John Hoaglun-2

Re: NG0R - KSB2 low audio level

Hi Don & group,

Yes, I have some test gear. I will run a test next weekend once I get
back from my next business trip.

73
--
John Hoaglun
NG0R - EN25
http://www.hoaglun.com

On Sun, 2011-01-16 at 21:07 -0500, Don Wilhelm wrote:

> John,
> power.
>
> If you do not have an oscilloscope, do you have a peak reading
> wattmeter? What does that meter say about the SSB peak power?
>
> What I am trying to discover is whether the problem is related to the
> base K2 or some problem with the transverters. Taking the transverters
> out of the picture and getting a reading on the behavior of the K2 on 40
> meters will be revealing.
>
> Please include the vintage (or serial number) of the K2 and when was the
> KSB2 option purchased?
>
> 73,
> Don W3FPR

John Hoaglun-2

Re: NG0R - KSB2 low audio level

In reply to this post by Don Wilhelm-4

Hi Don & list

Now that I am back from my business trip I am able to get back to the
work bench.

I put the K2 on the work bench tonight to run the test:
K2+20dB directional coupler+20dB pad : running @ 7.04mhz at 2w

CW vs SSB is about a 3dB difference on my Booton microwatt meter.

My oscope was showing a similar result.

The SSB levels appear to be down which is consistent with what I saw
last weekend when I was looking at this. It does not appear to have
anything to do with the transverters.

Any suggestions on where to look in the SSB or ALC circuits or someplace
else?

Thanks, JH

--
John Hoaglun
NG0R - EN25
http://www.hoaglun.com

On Sun, 2011-01-16 at 21:07 -0500, Don Wilhelm wrote:

> John,
>
> To answer your question, I suggest getting the transverters out of the
> equation - there are too many variables right now. Let's try to take it
> one step at a time.
>
> Do you have an oscilloscope? If so, try 40 meters into a dummy load -
> note the amplitude of a CW signal on the 'scope. Then switch to SSB and
> speak into the mic - are the SSB peaks as great as the CW amplitude?
> They should be. If they are, then the K2 is delivering the full PEP
> requested by the power control and you need to look for problems other
> than the K2, and your wattmeters may be indicating something other than
> the peak power.
>
> If you do not have an oscilloscope, do you have a peak reading
> wattmeter? What does that meter say about the SSB peak power?
>
> What I am trying to discover is whether the problem is related to the
> base K2 or some problem with the transverters. Taking the transverters
> out of the picture and getting a reading on the behavior of the K2 on 40
> meters will be revealing.
>
> Please include the vintage (or serial number) of the K2 and when was the
> KSB2 option purchased?
>
> 73,
> Don W3FPR
>
> On 1/16/2011 8:10 PM, John Hoaglun wrote:
> > I need some help troubleshooting an issue.
> >
> > K2+KSB2+K160RX+KIO2+KAT2+K60XV+XV144+XV222+XV432+IMA rework module
> >
> > I have not spent much time using this rig on SSB but I plan to use it to
> > drive the transverters. So as part of the setup& checkout of the system
> > I am noticing that my SSB power level seems pretty low compared to my CW
> > power level. Specifically when I test my transverters I am getting my
> > expected power on all of them with CW. (The transverter power level on
> > each unit is setup for driving the input power level for the brick for
> > that band.)
> >
> > 144: 25w CW --expected
> > 222: 10w CW --expected
> > 432: 10w CW --expected
> >
> > When I change over to SSB the power level is almost nothing
> > 144: 1-2w SSB
> > 222: less than 1w SSB
> > 432: less than 1w SSB
> >
> > I am using an Icom HM-36 mic (and have tested with two Heil headsets
> > with similar results). SSBA=3 and SSBC=4-1
> >
> > Initially I was thinking that I had an issue with Mic bias but I am not
> > so sure now. I configure my computer to send modulated CW over SSB to
> > compare the output level against a native CW signal. The spread matches
> > the info above.
> >
> > It appears that my SSB audio level is attenuated for some reason. (The
> > audio reports are good with no distortion.)
> >
> > Any suggestions for where to look on the KSB2 or an adjustment that I
> > might have missed?
> >
> > 73 de NG0R
> >

Don Wilhelm-4

Re: NG0R - KSB2 low audio level

John,

Welcome back.

What microphone are you using? And what is the compression set at?

In my experience, the K2 SSBC parameter should be set at 2:1 or higher
(I actually prefer 3:1) no matter what the microphone. The SSBA menu
parameter will (of course) depend on the microphone being used - SSBA =
1 for high output microphones and either SSBA = 2 or 3 for low output
microphones).

Bottom line - I would look at the mic levels first. If the compression
level does not even things out, then perhaps a microphone preamplifier
may be in order. If the mic is one using the Heil HC4 or HC5 element,
those are low output microphones and may need a pre-amp. Those
microphones with an electret element have high level output (like the
Elecraft MH2, MD2 or ProSet-K2) and do not need increased mic gain.

73,
Don W3FPR

On 1/22/2011 10:29 PM, John Hoaglun wrote:

> Hi Don& list
>
> Now that I am back from my business trip I am able to get back to the
> work bench.
>
> I put the K2 on the work bench tonight to run the test:
> K2+20dB directional coupler+20dB pad : running @ 7.04mhz at 2w
>
> CW vs SSB is about a 3dB difference on my Booton microwatt meter.
>
> My oscope was showing a similar result.
>
> The SSB levels appear to be down which is consistent with what I saw
> last weekend when I was looking at this. It does not appear to have
> anything to do with the transverters.
>
> Any suggestions on where to look in the SSB or ALC circuits or someplace
> else?
>
> Thanks, JH
>

John Hoaglun-2

Re: NG0R - KSB2 low audio level

Hi Don,

That info was in the email chain until your response trimmed down the message. :-)

I am using an (older) Icom HM-36 mic (and have tested with two Heil
headsets with similar results). The menu is set to: SSBA=3 and
SSBC=4-1 I also indicated that I had tested (during my original
testing) with a modulated CW signal from the computer as well with
similar results... the SSB audio is very low.

You had asked two other questions in the original email chain: The K2
S/N is 6119 and the SSB board was bought and assembled a couple of
years ago.

Looking at the schematic I am not seeing much in the way of adjustments
on the SSB circuit beyond the the compression at the SSM2165 which
controlled by the MCU.

A pre-amp is a kludgy solution IMO. (It might be ok to use it for a quick test
to see if that is the problem.)

Thoughts? Guidance from anyone else with a K2+HM-36 ?

Thanks, JH

--
John Hoaglun
NG0R - EN25
http://www.hoaglun.com

On Sat, 2011-01-22 at 23:03 -0500, Don Wilhelm wrote:

> John,
>
> Welcome back.
>
> What microphone are you using? And what is the compression set at?
>
> In my experience, the K2 SSBC parameter should be set at 2:1 or higher
> (I actually prefer 3:1) no matter what the microphone. The SSBA menu
> parameter will (of course) depend on the microphone being used - SSBA =
> 1 for high output microphones and either SSBA = 2 or 3 for low output
> microphones).
>
> Bottom line - I would look at the mic levels first. If the compression
> level does not even things out, then perhaps a microphone preamplifier
> may be in order. If the mic is one using the Heil HC4 or HC5 element,
> those are low output microphones and may need a pre-amp. Those
> microphones with an electret element have high level output (like the
> Elecraft MH2, MD2 or ProSet-K2) and do not need increased mic gain.
>
> 73,
> Don W3FPR
>
> On 1/22/2011 10:29 PM, John Hoaglun wrote:
> > Hi Don& list
> >
> > Now that I am back from my business trip I am able to get back to the
> > work bench.
> >
> > I put the K2 on the work bench tonight to run the test:
> > K2+20dB directional coupler+20dB pad : running @ 7.04mhz at 2w
> >
> > CW vs SSB is about a 3dB difference on my Booton microwatt meter.
> >
> > My oscope was showing a similar result.
> >
> > The SSB levels appear to be down which is consistent with what I saw
> > last weekend when I was looking at this. It does not appear to have
> > anything to do with the transverters.
> >
> > Any suggestions on where to look in the SSB or ALC circuits or someplace
> > else?
> >
> > Thanks, JH
> >

Don Wilhelm-4

Re: NG0R - KSB2 low audio level

John,

OK, I am done with this thread. If one has to drill down in prior
emails to get the information needed, I cannot help. Maybe someone else
will remember your thread and come to your aid.
This is a volunteer effort on my part and I do not wish to be asked to
do extra-ordinary things to help.
If you want a paid position to come to your aid, then the folks at
[hidden email] are available.
I offer what I can, but I will am not willing to help if criticized for
shortening a thread in a response.

73,
Don W3FPR

On 1/22/2011 11:46 PM, John Hoaglun wrote:

> Hi Don,
>
> That info was in the email chain until your response trimmed down the message. :-)
>
> I am using an (older) Icom HM-36 mic (and have tested with two Heil
> headsets with similar results). The menu is set to: SSBA=3 and
> SSBC=4-1 I also indicated that I had tested (during my original
> testing) with a modulated CW signal from the computer as well with
> similar results... the SSB audio is very low.
>
> You had asked two other questions in the original email chain: The K2
> S/N is 6119 and the SSB board was bought and assembled a couple of
> years ago.
>
> Looking at the schematic I am not seeing much in the way of adjustments
> on the SSB circuit beyond the the compression at the SSM2165 which
> controlled by the MCU.
>
> A pre-amp is a kludgy solution IMO. (It might be ok to use it for a quick test
> to see if that is the problem.)
>
> Thoughts? Guidance from anyone else with a K2+HM-36 ?
>
>
> Thanks, JH
>

John Hoaglun-2

Re: NG0R - KSB2 low audio level

Don,

There was no criticism intended towards you or your volunteer effort
what so ever so. I went out of my way to try include as much of the
basic info as possible to reduce the initial "dance" of basic questions
by providing that info up front. --no harm or foul by anyone.

If you were offended please don't be as that was not the intent. Please
put one leaded or unleaded beverage of your choice on my tab.

I believe that this is a hobby which means that we do it because we
enjoy it. :-)

73
--
John Hoaglun
NG0R - EN25
http://www.hoaglun.com

On Sun, 2011-01-23 at 00:44 -0500, Don Wilhelm wrote:

> John,
>
> OK, I am done with this thread. If one has to drill down in prior
> emails to get the information needed, I cannot help. Maybe someone else
> will remember your thread and come to your aid.
> This is a volunteer effort on my part and I do not wish to be asked to
> do extra-ordinary things to help.
> If you want a paid position to come to your aid, then the folks at
> [hidden email] are available.
> I offer what I can, but I will am not willing to help if criticized for
> shortening a thread in a response.
>
> 73,
> Don W3FPR

John Hoaglun-2

NG0R - KSB2 low audio level

In reply to this post by John Hoaglun-2

I need some help troubleshooting an issue.

K2+KSB2+K160RX+KIO2+KAT2+K60XV+XV144+XV222+XV432+IMA rework module

I have not spent much time using this rig on SSB but I plan to use it to
drive some transverters. So as part of the setup & checkout of the
system
I am noticing that my SSB power level seems pretty low compared to my CW
power level. Specifically when I test my transverters I am getting my
expected power on all of them with CW. (The transverter power level on
each unit is setup for driving the input power level for the brick for
that band.)

144: 25w CW --expected
222: 10w CW --expected
432: 10w CW --expected

When I change over to SSB the power level is almost nothing (even with
modulated CW)
144: 1-2w SSB --lower than expected
222: less than 1w SSB --lower than expected
432: less than 1w SSB --lower than expected

Following Don's suggestion I tested the K2 independent of the
tranverters & interfaces. (K2+20dB dir coupler+20dB pad)
On 40m my Booton microwatt meter and oscope show that on SSB at peak I
am only making about 50-60% of the power that I am on CW. (About 3 dB
down)

I have tried a couple of different bias approaches with the IMA rework
module and the results are the same. (The recommend config is 10k which
is where I started.)

I am using an (older) Icom HM-36 mic (and have tested with two Heil
headsets
with similar results). The menu is set to SSBA=3 and SSBC=4-1

There are are probably some other folks using a similar mic
configuration and I am curious what their experience has been. Maybe
there is some guidance from the group based upon their experience.

73 de NG0R

--
John Hoaglun
NG0R - EN25
http://www.hoaglun.com

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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